CERN: Antimatter in the trap

Schematic drawing of the ALPHA experiment: antiprotons are captured and held in ultrahigh vacuum using electric and magnetic fields. Mixing them with positrons, the antihydrogen atoms are formed and confined using an octupole magnetic trap and mirror coils Image courtesy of CERN

December 2011 - Precision studies of antimatter - the elusive counterpart of matter - should help scientists to find out why all antimatter produced in the Big Bang has disappeared. The most promising new ‘anti-object’ is antihydrogen, the simplest element in a hypothetical anti-world.

The first nine antimatter atoms ever were produced at CERN in 1995, but they moved almost with the speed of light - too fast for precision studies. The next breakthrough came in 2002, when the ATHENA experiment showed how to make millions of slow-moving antihydrogen atoms. But it has taken another nine years for the next step - trapping a few of them. Now researchers from the ALPHA experiment at CERN have succeeded in trapping 38 anti-atoms for 172 milliseconds. In July 2011, they announced that they had managed to keep a few hundred of them for as long as 15 minutes. This paves the way for a precision comparison of the energy levels between hydrogen and antihydrogen, using ultra-precise laser systems.

To learn more, see the research publication: The ALPHA Collaboration (2011) Confinement of antihydrogen for 1000 seconds. Nature Physics 7: 558-564. doi: 10.1038/nphys2025